/****************************************************************************
*
* NAME: PitchShift
* VERSION: 1.2
* HOME URL: http://www.dspdimension.com
* KNOWN BUGS: none
*
* SYNOPSIS: Routine for doing pitch shifting while maintaining
* duration using the Short Time Fourier Transform.
*
* DESCRIPTION: The routine takes a pitchShift factor value which is between 0.5
* (one octave down) and 2. (one octave up). A value of exactly 1 does not change
* the pitch. numSampsToProcess tells the routine how many samples in indata[0...
* numSampsToProcess-1] should be pitch shifted and moved to outdata[0 ...
* numSampsToProcess-1]. The two buffers can be identical (ie. it can process the
* data in-place). fftFrameSize defines the FFT frame size used for the
* processing. Typical values are 1024, 2048 and 4096. It may be any value <=
* MAX_FRAME_LENGTH but it MUST be a power of 2. osamp is the STFT
* oversampling factor which also determines the overlap between adjacent STFT
* frames. It should at least be 4 for moderate scaling ratios. A value of 32 is
* recommended for best quality. sampleRate takes the sample rate for the signal
* in unit Hz, ie. 44100 for 44.1 kHz audio. The data passed to the routine in
* indata[] should be in the range [-1.0, 1.0), which is also the output range
* for the data, make sure you scale the data accordingly (for 16bit signed integers
* you would have to divide (and multiply) by 32768).
*
* COPYRIGHT 1999-2006 Stephan M. Bernsee <smb [AT] dspdimension [DOT] com>
*
*                       The Wide Open License (WOL)
*
* Permission to use, copy, modify, distribute and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice and this license appear in all source copies.
* THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT EXPRESS OR IMPLIED WARRANTY OF
* ANY KIND. See http://www.dspguru.com/wol.htm for more information.
*
*****************************************************************************/

// Adapted from https://github.com/Collaboarator/ShortTimeFourierPitchShifterJS

var AudioContext = window.AudioContext || window.webkitAudioContext;
var audioCtx = new AudioContext();

export function pitchShiftFile(audioBuffer, volume, shiftAmount) {
    var decodedData = audioBuffer;
    if (shiftAmount != 1.0) {
        // Copy buffer
        decodedData = audioCtx.createBuffer(audioBuffer.numberOfChannels, audioBuffer.length, audioBuffer.sampleRate);
        for(let i = 0; i < audioBuffer.numberOfChannels;i++) {
            decodedData.copyToChannel(audioBuffer.getChannelData(i), i);

            var in_data_l = decodedData.getChannelData(i);
            //console.log(in_data_l);
            //var in_data_r=decodedData.getChannelData(1);
            //console.log(in_data_r);
            //console.log(shiftAmount);
            in_data_l = PitchShift(shiftAmount, in_data_l.length, 1024, 10, audioCtx.sampleRate, in_data_l);
            //console.log(in_data_l);
            //in_data_r= PitchShift(shiftAmount, in_data_r.length, 1024, 10, audioCtx.sampleRate, in_data_r);
            decodedData.copyToChannel(in_data_l, i);
            //decodedData.copyToChannel(in_data_r, 1);
        }
    }
    var source = audioCtx.createBufferSource(); // creates a sound source
    source.buffer = decodedData;       // tell the source which sound to play
    //console.log('starting');

    // Set volume
    var gainNode = audioCtx.createGain();
    gainNode.gain.value = volume;
    gainNode.connect(audioCtx.destination);

    source.connect(gainNode);       // connect the source to the context's destination (the speakers)
    source.start(0);                            // play the source now

    return source;
}

function loadTheTrack()
{
    var input = document.createElement('input');
    input.type = 'file';
    input.style = 'display:none';
    input.onchange = function (e) {
        var file = e.target.files[0];
        console.log(file);
        var reader = new FileReader();
        reader.onload = function () {
            console.log('decoding audio data with' + this.result);
            document.getElementById('status').innerText = 'Pitch Shifting (yeah it takes a min)....';
            audioCtx.decodeAudioData(this.result, (decodedData) => {
                var in_data_l = decodedData.getChannelData(0);
                console.log(in_data_l);
                var in_data_r = decodedData.getChannelData(1);
                console.log(in_data_r);
                var shiftAmount = document.getElementById('shiftAmount').value;
                console.log(shiftAmount);
                in_data_l = PitchShift(shiftAmount, in_data_l.length, 1024, 10, audioCtx.sampleRate, in_data_l);
                console.log(in_data_l);
                in_data_r = PitchShift(shiftAmount, in_data_r.length, 1024, 10, audioCtx.sampleRate, in_data_r);
                decodedData.copyToChannel(in_data_l, 0);
                decodedData.copyToChannel(in_data_r, 1);
                var source = audioCtx.createBufferSource(); // creates a sound source
                source.buffer = decodedData;       // tell the source which sound to play
                source.connect(audioCtx.destination);       // connect the source to the context's destination (the speakers)
                console.log('starting');
                document.getElementById('status').innerText = 'Playing...';
                source.start(0);                            // play the source now
            }, (e) => {
                alert('Sorry this browser unable to download this file... try Chrome');
            });
        };
        reader.readAsArrayBuffer(file);
    };
    document.getElementById('wrapper').appendChild(input);
    input.click();
}

function PitchShift(/* float[*/ pitchShift, /* long */ numSampsToProcess, /* long */ fftFrameSize,
    /* long */ osamp, /* float[*/ sampleRate, /* float[] */ indata) {
    /* double */ var magn, phase, tmp, window, real, imag;
    /* double */ var freqPerBin, expct;
    /* long */ var i, k, qpd, index, inFifoLatency, stepSize, fftFrameSize2;

    const MAX_FRAME_LENGTH = 16000;
    var gInFIFO = new Array(MAX_FRAME_LENGTH).fill(0.0);
    var gOutFIFO = new Array(MAX_FRAME_LENGTH).fill(0.0);
    var gFFTworksp = new Array(2 * MAX_FRAME_LENGTH).fill(0.0);
    var gLastPhase = new Array(MAX_FRAME_LENGTH / 2 + 1).fill(0.0);
    var gSumPhase = new Array(MAX_FRAME_LENGTH / 2 + 1).fill(0.0);
    var gOutputAccum = new Array(2 * MAX_FRAME_LENGTH).fill(0.0);
    var gAnaFreq = new Array(MAX_FRAME_LENGTH).fill(0.0);
    var gAnaMagn = new Array(MAX_FRAME_LENGTH).fill(0.0);
    var gSynFreq = new Array(MAX_FRAME_LENGTH).fill(0.0);
    var gSynMagn = new Array(MAX_FRAME_LENGTH).fill(0.0);
    var gRover = 0;

    /* float[] */var outdata = indata;
    /* set up some handy variables */
    fftFrameSize2 = Math.trunc(fftFrameSize / 2);
    stepSize = Math.trunc(fftFrameSize / osamp);
    freqPerBin = sampleRate / /* (double) */fftFrameSize;
    expct = 2.0 * Math.PI * /* (double) */stepSize / /* (double) */fftFrameSize;
    inFifoLatency = Math.trunc(fftFrameSize - stepSize);
    if (gRover == 0) gRover = inFifoLatency;


    /* main processing loop */
    for (i = 0; i < numSampsToProcess; i++) {

        /* As long as we have not yet collected enough data just read in */
        gInFIFO[gRover] = indata[i];
        outdata[i] = gOutFIFO[gRover - inFifoLatency];
        gRover++;

        /* now we have enough data for processing */
        if (gRover >= fftFrameSize) {
            gRover = inFifoLatency;

            /* do windowing and re,im interleave */
            for (k = 0; k < fftFrameSize; k++) {
                window = -.5 * Math.cos(2.0 * Math.PI * /* (double) */k / /* (double) */fftFrameSize) + .5;
                gFFTworksp[2 * k] = /* (float) */(gInFIFO[k] * window);
                gFFTworksp[2 * k + 1] = 0.0;
            }


            /* ***************** ANALYSIS ******************* */
            /* do transform */
            ShortTimeFourierTransform(gFFTworksp, fftFrameSize, -1);

            /* this is the analysis step */
            for (k = 0; k <= fftFrameSize2; k++) {

                /* de-interlace FFT buffer */
                real = gFFTworksp[2 * k];
                imag = gFFTworksp[2 * k + 1];

                /* compute magnitude and phase */
                magn = 2.0 * Math.sqrt(real * real + imag * imag);
                phase = Math.atan2(imag, real);

                /* compute phase difference */
                tmp = phase - gLastPhase[k];
                gLastPhase[k] = /* (float) */phase;

                /* subtract expected phase difference */
                tmp -= /* (double) */k * expct;

                /* map delta phase into +/- Pi interval */
                qpd = /* (long) */Math.trunc(tmp / Math.PI);
                if (qpd >= 0) qpd += qpd & 1;
                else qpd -= qpd & 1;
                tmp -= Math.PI * /* (double) */qpd;

                /* get deviation from bin frequency from the +/- Pi interval */
                tmp = osamp * tmp / (2.0 * Math.PI);

                /* compute the k-th partials' true frequency */
                tmp = /* (double) */k * freqPerBin + tmp * freqPerBin;

                /* store magnitude and true frequency in analysis arrays */
                gAnaMagn[k] = /* (float) */magn;
                gAnaFreq[k] = /* (float) */tmp;

            }

            /* ***************** PROCESSING ******************* */
            /* this does the actual pitch shifting */
            for (var zero = 0; zero < fftFrameSize; zero++) {
                gSynMagn[zero] = 0;
                gSynFreq[zero] = 0;
            }

            for (k = 0; k <= fftFrameSize2; k++) {
                index = /* (long) */Math.trunc(k * pitchShift);
                if (index <= fftFrameSize2) {
                    gSynMagn[index] += gAnaMagn[k];
                    gSynFreq[index] = gAnaFreq[k] * pitchShift;
                }
            }

            /* ***************** SYNTHESIS ******************* */
            /* this is the synthesis step */
            for (k = 0; k <= fftFrameSize2; k++) {

                /* get magnitude and true frequency from synthesis arrays */
                magn = gSynMagn[k];
                tmp = gSynFreq[k];

                /* subtract bin mid frequency */
                tmp -= /* (double) */k * freqPerBin;

                /* get bin deviation from freq deviation */
                tmp /= freqPerBin;

                /* take osamp into account */
                tmp = 2.0 * Math.PI * tmp / osamp;

                /* add the overlap phase advance back in */
                tmp += /* (double) */k * expct;

                /* accumulate delta phase to get bin phase */
                gSumPhase[k] += /* (float) */tmp;
                phase = gSumPhase[k];

                /* get real and imag part and re-interleave */
                gFFTworksp[2 * k] = /* (float) */(magn * Math.cos(phase));
                gFFTworksp[2 * k + 1] = /* (float) */(magn * Math.sin(phase));
            }

            /* zero negative frequencies */
            for (k = fftFrameSize + 2; k < 2 * fftFrameSize; k++) gFFTworksp[k] = 0.0;

            /* do inverse transform */
            ShortTimeFourierTransform(gFFTworksp, fftFrameSize, 1);

            /* do windowing and add to output accumulator */
            for (k = 0; k < fftFrameSize; k++) {
                window = -.5 * Math.cos(2.0 * Math.PI * /* (double) */k / /* (double) */fftFrameSize) + .5;
                gOutputAccum[k] += /* (float) */(2.0 * window * gFFTworksp[2 * k] / (fftFrameSize2 * osamp));
            }
            for (k = 0; k < stepSize; k++) gOutFIFO[k] = gOutputAccum[k];

            /* shift accumulator */
            //memmove(gOutputAccum, gOutputAccum + stepSize, fftFrameSize * sizeof(float));
            for (k = 0; k < fftFrameSize; k++) {
                gOutputAccum[k] = gOutputAccum[k + stepSize];
            }

            /* move input FIFO */
            for (k = 0; k < inFifoLatency; k++) gInFIFO[k] = gInFIFO[k + stepSize];
        }
    }
    return outdata;
}

function ShortTimeFourierTransform(/* float[] */ fftBuffer, /* long */ fftFrameSize, /* long */ sign) {
    /* float */ var wr, wi, arg, temp;
    /* float */ var tr, ti, ur, ui;
    /* long */ var i, bitm, j, le, le2, k;

    for (i = 2; i < 2 * fftFrameSize - 2; i += 2) {
        for (bitm = 2, j = 0; bitm < 2 * fftFrameSize; bitm <<= 1) {
            if ((i & bitm) != 0) j++;
            j <<= 1;
        }
        if (i < j) {
            temp = fftBuffer[i];
            fftBuffer[i] = fftBuffer[j];
            fftBuffer[j] = temp;
            temp = fftBuffer[i + 1];
            fftBuffer[i + 1] = fftBuffer[j + 1];
            fftBuffer[j + 1] = temp;
        }
    }
    /* long */ var max = /* (long) */Math.trunc(Math.log(fftFrameSize) / Math.log(2.0) + .5);
    for (k = 0, le = 2; k < max; k++) {
        le <<= 1;
        le2 = le >> 1;
        ur = 1.0;
        ui = 0.0;
        arg = /* (float) */Math.PI / (le2 >> 1);
        wr = /* (float) */Math.cos(arg);
        wi = /* (float) */(sign * Math.sin(arg));
        for (j = 0; j < le2; j += 2) {

            for (i = j; i < 2 * fftFrameSize; i += le) {
                tr = fftBuffer[i + le2] * ur - fftBuffer[i + le2 + 1] * ui;
                ti = fftBuffer[i + le2] * ui + fftBuffer[i + le2 + 1] * ur;
                fftBuffer[i + le2] = fftBuffer[i] - tr;
                fftBuffer[i + le2 + 1] = fftBuffer[i + 1] - ti;
                fftBuffer[i] += tr;
                fftBuffer[i + 1] += ti;

            }
            tr = ur * wr - ui * wi;
            ui = ur * wi + ui * wr;
            ur = tr;
        }
    }
}
